If I took a Custom ROM and installed it as a update.zip file, from a completely stock phone and recovery image. I have a buddy that wants to join the family and it has been a really long time since I rooted anything.

If that up above was confusing, I would like to know the fastest way with the least amount of resources to use to root a stock phone. Nandroid backup is irrelevant in this case assuming I can update the phone to a custom ROM without any issues and use ClockWork Mod.